Chevrolet Repair: low coolant light is on in my 1993 Corisica, coolant level, radiator cap

Question
My 1993 4 door Corsica's low coolant light just started coming on. I checked the resevoir, and even added some coolant, but that didn't solve the problem. My neighbor suggested that I add coolant directly to the radiator, but I don't see a place to do that. The other thought that I have, is that maybe it is a sensor. I believe the engine is a 4liter, but am not sure. Any help would be greatly appreciated.
Thank you,
Kevin B

Answer
Hi Kevin,

A sensor is meant to communicate with the computer.  An indicator talks with your guages.  Indicators going bad are not critical, and therefore don't turn trouble lights on.  Is your check engine light on?  If not, it probably is not a sensor.  

Do you have guages and this 'low coolant' light?  If so, the light is probably connected to the overflow bottle.  It will tell you when the overflow is in need of a topoff.  Putting coolant here is the right thing to do.  If you can physically see that the Coolant level is higher than the indicator, then you may have a bad indicator.  Most likely not.

It may be time for a flush and fill of the cooling system.  This will top off the coolant and replace the old acetic stuff with fresh new stuff.  Better for the motor and should be done every 2 years.  

It is possible you have a low coolant indicator plugged into the motor somewhere.  If so, and this is the light's source, then fill the radiator.  Look for a radiator cap.  However if you don't see one, then use the overflow bottle.  Sometimes this is the only way.  Make sure you use the right color coolant.  Bleed off the cooling system if you have bleeder screws.  

Good luck.

C J S